Method of and apparatus for producing thin metallic sheet by rapid cooling

Abstract

A double roll type method and apparatus for producing a thin metallic sheet by pouring a molten metal of a desired composition into a kissing region between two cooling rolls rotating in opposite directions, and rapidly cooling and solidifying the molten metal while it passes through the kissing region. The thin sheet which has come out of the kissing region is forcibly deflected by gas from a gas applying head and by a pair of pinch rolls so as to make close contact with one of the two cooling rolls over a predetermined region in the circumferential direction of the roll.

What is claimed is: 
     
       1. A double roll type method of producing a thin sheet by rapid cooling, comprising the steps of: pouring molten metal into a kissing region between a pair of cooling rolls rotating in opposite directions;   rapidly cooling and solidifying the molten metal into a thin sheet while said molten metal passes through said kissing region;   applying a cooling gas to the thin sheet coming out of said kissing region to further cool the thin sheet and to deflect the thin sheet towards a surface of one of said cooling rolls so as to bring the thin sheet in contact with said surface of said one of said cooling rolls; and   imparting a tension to the thin sheet by a pair of pinch rolls disposed at a downstream side of a position of application of said cooling gas, whereby the thin sheet is kept in close contact with said surface of said one of said cooling rolls over a predetermined region in a circumferential direction of said surface.   
     
     
       2. A method of producing a thin sheet as claimed in claim 1, wherein said thin sheet coming out of said kissing region is held in close contact with the surface of said one of said cooling rolls over a circumferential angular region of about 90°. 
     
     
       3. A double roll type apparatus for producing a thin sheet by rapid cooling, comprising: a pair of cooling rolls rotating in opposite directions forming a kissing region between said cooling rolls wherein a molten metal is poured into said kissing region and the molten metal is rapidly cooled and solidified to become a thin sheet as it passes through said kissing region;   a gas applying header disposed downstream from and in the vicinity of said kissing region to apply a cooling gas to a surface of said thin sheet so as to deflect said thin sheet towards one of said cooling rolls; and   a pair of pinch rolls disposed downstream from said gas applying header, said pinch rolls rotating in synchronism with said cooling rolls thereby to impart a tension to said thin sheet, whereby said gas applying header and said pinch rolls cooperate with each other in deflecting said thin sheet into close contact with the surface of said one of said cooling rolls over a predetermined region in the circumferential direction of said cooling roll, thereby to further cool said thin sheet rapidly.   
     
     
       4. An apparatus for producing a thin sheet as claimed in claim 3, wherein the cooling rool contacted by said thin sheet over said predetermined region has a diameter greater than that of the other cooling roll. 
     
     
       5. An apparatus for producing a thin sheet according to claim 4, wherein the diameter D 1  of the larger cooling roll and the diameter D 2  of the smaller cooling roll are determined to meet the following condition:   1.5≦D.sub.1 /D.sub.2 ≦2.5.     
     
     
       6. An apparatus for producing a thin sheet according to claim 3, further comprising a guide disposed between said gas applying header and said pinch rolls to guide said thin sheet towards said pinch rolls. 
     
     
       7. An apparatus for producing a thin sheet as claimed in claim 6, further comprising a gas applying header disposed in the vicinity of the inlet side of said pinch rolls for applying a cooling gas for cooling said thin sheet and guiding said thin sheet to a kissing region between said pinch rolls. 
     
     
       8. An apparatus for producing a thin sheet as claimed in claim 3, further comprising: a take-up reel disposed at the outlet side of said pinch rolls;   a suitable number of gas applying headers arranged around said take-up reel to apply a cooling gas to said thin sheet; and   guides arranged around said take-up reel.